{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T00:49:41Z","timestamp":1771634981501,"version":"3.50.1"},"reference-count":31,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2024,4,16]],"date-time":"2024-04-16T00:00:00Z","timestamp":1713225600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004543","name":"China Scholarship Council","doi-asserted-by":"publisher","award":["202106370009"],"award-info":[{"award-number":["202106370009"]}],"id":[{"id":"10.13039\/501100004543","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Pupil size is a significant biosignal for human behavior monitoring and can reveal much underlying information. This study explored the effects of task load, task familiarity, and gaze position on pupil response during learning a visual tracking task. We hypothesized that pupil size would increase with task load, up to a certain level before decreasing, decrease with task familiarity, and increase more when focusing on areas preceding the target than other areas. Fifteen participants were recruited for an arrow tracking learning task with incremental task load. Pupil size data were collected using a Tobii Pro Nano eye tracker. A 2 \u00d7 3 \u00d7 5 three-way factorial repeated measures ANOVA was conducted using R (version 4.2.1) to evaluate the main and interactive effects of key variables on adjusted pupil size. The association between individuals\u2019 cognitive load, assessed by NASA-TLX, and pupil size was further analyzed using a linear mixed-effect model. We found that task repetition resulted in a reduction in pupil size; however, this effect was found to diminish as the task load increased. The main effect of task load approached statistical significance, but different trends were observed in trial 1 and trial 2. No significant difference in pupil size was detected among the three gaze positions. The relationship between pupil size and cognitive load overall followed an inverted U curve. Our study showed how pupil size changes as a function of task load, task familiarity, and gaze scanning. This finding provides sensory evidence that could improve educational outcomes.<\/jats:p>","DOI":"10.3390\/s24082545","type":"journal-article","created":{"date-parts":[[2024,4,16]],"date-time":"2024-04-16T04:21:59Z","timestamp":1713241319000},"page":"2545","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Pupil Response in Visual Tracking Tasks: The Impacts of Task Load, Familiarity, and Gaze Position"],"prefix":"10.3390","volume":"24","author":[{"given":"Yun","family":"Wu","sequence":"first","affiliation":[{"name":"Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5836-7257","authenticated-orcid":false,"given":"Zhongshi","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5371-2392","authenticated-orcid":false,"given":"Yao","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3476-5936","authenticated-orcid":false,"given":"Bin","family":"Zheng","sequence":"additional","affiliation":[{"name":"Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2S2, Canada"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4377-7595","authenticated-orcid":false,"given":"Farzad","family":"Aghazadeh","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, University of Alberta, Edmonton, AB T6G 2S2, Canada"}]}],"member":"1968","published-online":{"date-parts":[[2024,4,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"112325","DOI":"10.1016\/j.ijpsycho.2024.112325","article-title":"Effect of Recurrent Task-Induced Acute Stress on Task Performance, Vagally Mediated Heart Rate Variability, and Task-Evoked Pupil Response","volume":"198","author":"Nuamah","year":"2024","journal-title":"Int. J. Psychophysiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"258","DOI":"10.1016\/j.jss.2022.07.010","article-title":"The Measurement of Cognitive Workload in Surgery Using Pupil Metrics: A Systematic Review and Narrative Analysis","volume":"280","author":"Naik","year":"2022","journal-title":"J. Surg. Res."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"647","DOI":"10.1007\/s10072-020-04533-z","article-title":"Pupil Dilation as an Indicator of Future Thinking","volume":"42","author":"Moustafa","year":"2021","journal-title":"Neurol. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1177\/1745691611427305","article-title":"Pupillometry: A Window to the Preconscious?","volume":"7","author":"Laeng","year":"2012","journal-title":"Perspect. Psychol. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"371","DOI":"10.3758\/BF03328444","article-title":"Pupillary Changes in Two Memory Tasks","volume":"5","author":"Beatty","year":"1966","journal-title":"Psychon. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1583","DOI":"10.1126\/science.154.3756.1583","article-title":"Pupil Diameter and Load on Memory","volume":"154","author":"Kahneman","year":"1966","journal-title":"Science"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Krejtz, K., \u017burawska, J., Duchowski, A.T., and Wichary, S. (2020). Pupillary and Microsaccadic Responses to Cognitive Effort and Emotional Arousal During Complex Decision Making. J. Eye Mov. Res., 13.","DOI":"10.16910\/jemr.13.5.2"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"592","DOI":"10.3758\/s13415-020-00843-z","article-title":"Task-Evoked Pupillary Responses Track Effort Exertion: Evidence from Task-Switching","volume":"21","author":"LoParco","year":"2021","journal-title":"Cogn. Affect. Behav. Neurosci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2005","DOI":"10.3758\/s13423-018-1432-y","article-title":"Pupil Dilation as an Index of Effort in Cognitive Control Tasks: A Review","volume":"25","year":"2018","journal-title":"Psychon. Bull. Rev."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1177\/001872088903100503","article-title":"A Dynamic Model of Stress and Sustained Attention","volume":"31","author":"Hancock","year":"1989","journal-title":"Hum. Factors"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1002\/cne.920180503","article-title":"The Relation of Strength of Stimulus to Rapidity of Habit-Formation","volume":"18","author":"Yerkes","year":"1908","journal-title":"J. Comp. Neurol. Psychol."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Paas, F., Tuovinen, J.E., Tabbers, H., and Van Gerven, P.W. (2016). Cognitive Load Theory, Routledge.","DOI":"10.4324\/9780203764770"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1111\/j.1469-8986.2003.00148.x","article-title":"Memory Load and the Cognitive Pupillary Response in Aging","volume":"41","author":"Paas","year":"2004","journal-title":"Psychophysiology"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1289","DOI":"10.1126\/science.472746","article-title":"Pupillary Responses during Information Processing Vary with Scholastic Aptitude Test Scores","volume":"205","author":"Ahern","year":"1979","journal-title":"Science"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1037\/a0038653","article-title":"The Pupillary Light Response Reflects Eye-Movement Preparation","volume":"41","author":"Grainger","year":"2015","journal-title":"J. Exp. Psychol. Hum. Percept. Perform."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1177\/0963721415593725","article-title":"New Light on the Mind\u2019s Eye: The Pupillary Light Response as Active Vision","volume":"24","year":"2015","journal-title":"Curr. Dir. Psychol. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1704","DOI":"10.1073\/pnas.0707727105","article-title":"Pupil Dilation Reflects Perceptual Selection and Predicts Subsequent Stability in Perceptual Rivalry","volume":"105","author":"Stout","year":"2008","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1815","DOI":"10.1364\/AO.515579","article-title":"Optimized Design of a Gravitational Wave Telescope System Based on Pupil Aberration","volume":"63","author":"Song","year":"2024","journal-title":"Appl. Opt."},{"key":"ref_19","first-page":"139","article-title":"Developing the Emotion Regulation Skills of Autistic Pupils in Educational Settings: A Systematic Literature Review","volume":"52","author":"Bennett","year":"2024","journal-title":"J. Res. Spec. Educ. Needs"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1348\/000711001159357","article-title":"The Analysis of Repeated Measures Designs: A Review","volume":"54","author":"Keselman","year":"2001","journal-title":"Br. J. Math. Stat. Psychol."},{"key":"ref_21","unstructured":"Hart, S.G., and Staveland, L.E. (1988). Advances in Psychology, Elsevier."},{"key":"ref_22","first-page":"165","article-title":"Detecting Assumption Violations in Mixed-Model Analysis of Variance","volume":"40","author":"Chiarotti","year":"2004","journal-title":"Ann Ist Super Sanita"},{"key":"ref_23","first-page":"40","article-title":"What is the Bonferroni Correction?","volume":"6","author":"Napierala","year":"2012","journal-title":"AAOS Now"},{"key":"ref_24","first-page":"1","article-title":"lme4: Linear Mixed-Effects Models Using Eigen and S4","volume":"1","author":"Bates","year":"2014","journal-title":"R Package Version"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1080\/00401706.1972.10488918","article-title":"Calculation of the Residual Sum of Squares for All Possible Regressions","volume":"14","author":"Morgan","year":"1972","journal-title":"Technometrics"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1037\/0033-2909.91.2.276","article-title":"Task-Evoked Pupillary Responses, Processing Load, and the Structure of Processing Resources","volume":"91","author":"Beatty","year":"1982","journal-title":"Psychol. Bull."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Ga\u0142ecki, A., Burzykowski, T., Ga\u0142ecki, A., and Burzykowski, T. (2013). Linear Mixed-Effects Model, Springer.","DOI":"10.1007\/978-1-4614-3900-4"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1002\/bjs.10795","article-title":"Systematic Review of Measurement Tools to Assess Surgeons\u2019 Intraoperative Cognitive Workload","volume":"105","author":"Dias","year":"2018","journal-title":"J. Br. Surg."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1111\/j.1469-8986.2007.00605.x","article-title":"Effects of Incentive on Working Memory Capacity: Behavioral and Pupillometric Data","volume":"45","author":"Heitz","year":"2008","journal-title":"Psychophysiology"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1123\/jsep.22.2.167","article-title":"Expertise Differences in Cortical Activation and Gaze Behavior During Rifle Shooting","volume":"22","author":"Janelle","year":"2000","journal-title":"J. Sport Exerc. Psychol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"24871","DOI":"10.1007\/s12144-022-03430-2","article-title":"Cognitive Load-Induced Pupil Dilation Reflects Potential Flight Ability","volume":"42","author":"Zheng","year":"2023","journal-title":"Curr. Psychol."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/8\/2545\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:28:31Z","timestamp":1760106511000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/8\/2545"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,4,16]]},"references-count":31,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2024,4]]}},"alternative-id":["s24082545"],"URL":"https:\/\/doi.org\/10.3390\/s24082545","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,4,16]]}}}